Key permission distribution

Patent metadata

Field	Value
Publication number	US-11494356-B2
Application number	US-202017029928-A
Country	US
Kind code	B2
Filing date	Sep 23, 2020
Priority date	Sep 23, 2020
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

Techniques are disclosed relating to the distribution of database key permissions. A database system may distribute first permission information to a plurality of database nodes that identifies a distribution of key range permissions to ones of the plurality of database nodes. A given key range permission being distributed to a given database node may permit that database node to write records whose keys fall within a key range associated with the given key range permission. The database system may receive, from a first database node, a request for a first key range permission provisioned to a second database node. The database system may modify the first permission information to derive second permission information that provisions the first key range permission to the first database node instead of the second database node. The database system may distribute the second permission information to ones of the plurality of database nodes.

First claim

What is claimed is:

1. A method, comprising:
distributing, by a database system, first permission information to a plurality of database nodes of the database system, wherein the first permission information identifies a distribution of key range permissions to ones of the plurality of database nodes, and wherein a given key range permission being distributed to a given database node permits the given database node to write records whose keys fall within a key range associated with the given key range permission;
receiving, by the database system from a first database node, a request for a first key range permission provisioned to a second database node;
modifying, by the database system, the first permission information to derive second permission information that provisions the first key range permission to the first database node instead of the second database node; and
distributing, by the database system, the second permission information to ones of the plurality of database nodes, wherein the second permission information defines a key range transaction commit number associated with a latest committed record for the first key range permission, and wherein the first database node is operable to:
determine whether a transaction commit number associated with the first database node satisfies a particular condition relative to the key range transaction commit number; and
in response to determining that the transaction commit number satisfies the particular condition, write a record for a particular key associated with the first key range permission.

2. The method of claim 1 , further comprising:
prior to modifying the first permission information, the database system:
sending, to the second database node, a request to relinquish the first key range permission, wherein the second database node is operable to relinquish the first key range permission in response to determining that the first key range permission is not being used in a set of active transactions being performed at the second database node; and
receiving, from the second database node, an indication that the first key range permission has been relinquished.

3. The method of claim 2 , wherein the first permission information provisions, to the second database node, a second key range permission that is a superset of the first key range permission, and wherein the second database node is operable to relinquish the first key range permission but retain the remaining portions of the second key range permission.

4. The method of claim 2 , wherein the indication specifies the key range transaction commit number associated with the latest committed record for the first key range permission.

5. The method of claim 1 , wherein the first database node is operable to:
determine whether a second transaction commit number associated with the first database node is greater than the key range transaction commit number; and
in response to determining that the second transaction commit number is not greater than the key range transaction commit number, retrieve, from a database node that committed the latest committed record, a record transaction commit number for a second particular key associated with the first key range permission.

6. The method of claim 5 , wherein the first database node is operable to:
prevent a record write for the second particular key in response to determining that the second transaction commit number associated with the first database node is not greater than the record transaction commit number.

7. The method of claim 5 , wherein the first database node is operable to:
write a record for the second particular key in response to determining that the second transaction commit number associated with the first database node is greater than the record transaction commit number.

8. The method of claim 1 , wherein the second permission information is stored in a trie data structure that includes a plurality of branches, a particular branch of which corresponds to the first key range permission.

9. The method of claim 8 , wherein distributing the second permission information to ones of the plurality of database nodes includes:
notifying the plurality of database nodes about the second permission information;
receiving, from the ones of the plurality of database nodes, information requests for the second permission information; and
returning the trie data structure in responses to the information requests.

10. A non-transitory computer readable medium having program instructions stored thereon that are executable by a database system to cause the database system to perform operations comprising:
distributing first permission information to a plurality of database nodes of the database system, wherein the first permission information identifies a distribution of key range permissions to ones of the plurality of database nodes, and wherein a given key range permission being distributed to a given database node permits the given database node to write records whose keys fall within a key range associated with the given key range permission;
receiving, from a first database node, a permission request for a first key range permission provisioned to a second database node;
modifying the first permission information to derive second permission information that provisions the first key range permission to the first database node instead of the second database node; and
distributing the second permission information to ones of the plurality of database nodes wherein the second permission information defines a key range transaction commit number associated with a latest committed record for the first key range permission, and wherein the first database node is operable to:
determine whether a transaction commit number associated with the first database node satisfies a particular condition relative to the key range transaction commit number; and
in response to determining that the transaction commit number satisfies the particular condition, write a record for a particular key associated with the first key range permission.

11. The medium of claim 10 , wherein the operations further comprise:
sending, to the second database node, a request to relinquish at least the first key range permission; and
prior to modifying the first permission information, receiving, from the second database node, an indication that the first key range permission and a second key range permission has been relinquished.

12. The medium of claim 11 , wherein the modifying of the first permission information is performed such that a superset key range permission is provisioned to the first database node, and wherein the superset key range permission includes the first key range permission and the second key range permission that was not requested by the first database node in the permission request.

13. The medium of claim 11 , wherein the indication specifies that the second database node committed, during a particular timeframe, a record for a key that falls within a key range associated with the first key range permission.

14. The medium of claim 10 , wherein the modifying of the first permission information is performed such that the second permission information includes an indication of whether another database node committed, during a particular timeframe, a record having a key that falls within a key range associated with the first key range permission.

15. A method, comprising:
provisioning, by a permission orchestrator database node of a database system, a first key range permission to a first worker database node of the database system, wherein th

Assignees

• Salesforce Com Inc

Inventors

• Helland Patrick James

Classifications

• G06F16/2246 Primary

  Trees, e.g. B+trees · CPC title

• G06F21/6227

  where protection concerns the structure of data, e.g. records, types, queries · CPC title

• G06F16/2379

  Updates performed during online database operations; commit processing · CPC title

• G06F16/284

  Relational databases · CPC title

• G06F21/6218 Primary

  to a system of files or objects, e.g. local or distributed file system or database · CPC title